Global IBA Selection Criteria |
The 500 IBAs were chosen under a set of rigorous guidelines using four criteria
Sites containing a significant population of a federally-listed Endangered or Threatened Species
These sites are important to ensure adequate habitat for those species most at risk of extinction. In almost all cases, these sites are already given legal protection under the Endangered Species Act because of the presence of listed species. For those migratory Endangered Species that disperse over large areas, the U.S. Fish & Wildlife Service designates ‘Critical Habitat’ to provide an added layer of protection throughout the year, so that breeding and wintering sites will still be in pristine condition when birds return there during their annual cycles.
Sites containing significant populations of species listed on the U.S. Watch List
The WatchList is a list of bird species of conservation concern prepared by independent scientists as an early warning mechanism for wildlife managers. By providing adequate protection to these species, and the sites and habitats upon which they depend, we can help to avoid the possibility that they will eventually have to be listed as Endangered. In addition to species on the Watch List, which focuses on migratory species, the IBA map also includes sites for significant populations of non-migratory gamebirds, such as Greater and Lesser Prairie-Chicken, Greater and Gunnison Sage-Grouse, and Mountain and Montezuma Quail, which would otherwise qualify for inclusion in the Watch List because of their small or declining populations.
Sites that contain significant populations of species with restricted ranges
These species, though sometimes locally common, are vulnerable because habitat alterations over relatively small areas can quickly have a severe effect on their populations. In some cases, the U.S. has a special responsibility to protect these species because they occur only within our borders, and therefore, if they are to survive at all, must do so on U.S. soil. Some areas, such as the Southern Appalachians, that contain concentrations of unique subspecies of birds that normally nest much further north are also included, as these populations will likely differentiate into new unique species at some point in the future.
Sites that contain large concentrations of migratory birds during some part of the year
Some waterfowl species congregate at wetlands in massive flocks during parts of their annual cycle. Shorebirds too depend on multiple stopover sites to refuel along their migration routes. The loss of any one of these crucial staging areas could have a catastrophic impact on populations already stressed by the hardship of migration. Seabirds gather in huge ‘cities’ to nest on cliffs and oceanic islands. These colonies are vulnerable to oil spills, introduced predators, and human disturbance. Other sites are included on the map because they provide a first landing point for migrant species crossing open water, such as High Island Texas on the Gulf Coast; because they contain large nesting concentrations of colonial waterbirds such as herons and egrets; or because they have unique topography and funnel migrating birds of prey into narrow corridors where thermals can assist their laborious migrations.